Nanomedicines are often recognized by the innate immune system as a threat, leading to unwanted clearance due to complement activation. This adverse reaction not only alters the bioavailability of the therapeutic but can also cause cardiopulmonary complications and death in a portion of the population. There is a need for tools for assessing complement response in the early stage of development of nanomedicines. Currently, quantifying complement-mediated response in vitro is limited because of the differences between in vitro and in vivo responses for the same precursors, differences in the complement systems in different species, and lack of highly sensitive tools for quantifying the changes. Hence, we have worked on developing complement assay conditions and sample preparation techniques that can be highly sensitive in assessing the complement-mediated response in vitro mimicking the in vivo activity. We are screening the impact of incubation time, nanoparticle dosage, anticoagulants, and species of the donor in both blood and blood components. We have validated the optimal assay conditions by replicating the impact of zeta potential seen in vivo on complement activation in vitro. As observed in our previous in vivo studies, where nanoparticles with neutral zeta potential were able to suppress the complement response, the change in the complement biomarker was least for the neutral nanoparticles as well through our developed guidelines. These assay conditions provide a vital tool for assessing the safety of intravenously administered nanomedicines.

中文翻译：

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开发用于在体外筛选纳米颗粒以进行补体激活的灵敏测定法

纳米药物通常被先天免疫系统识别为威胁，由于补体激活导致不需要的清除。这种不良反应不仅会改变治疗剂的生物利用度，还会导致部分人群出现心肺并发症和死亡。需要在纳米药物开发的早期阶段评估补体反应的工具。目前，由于相同前体的体外和体内反应之间存在差异、不同物种补体系统的差异以及缺乏用于量化变化的高度敏感的工具，因此量化体外补体介导的反应受到限制。因此，我们致力于开发补体测定条件和样品制备技术，这些技术在评估体外补体介导的模拟体内活性的反应时具有高度敏感性。我们正在筛选潜伏期、纳米颗粒剂量、抗凝剂和供体种类对血液和血液成分的影响。我们通过复制体内 zeta 电位对体外补体激活的影响，验证了最佳测定条件。正如我们之前的体内研究中所观察到的，具有中性 zeta 电位的纳米粒子能够抑制补体反应，补体生物标志物的变化对于中性纳米粒子以及我们制定的指南来说都是最少的。